actinodromous

List of plant morphology terms

Biologists that study plant morphology use a number of different terms to describe plant organs and parts that can be observed with the human eye using no more than a hand held magnifying lens. These terms are used to identify and classify plants.

General plant terms

Abaxial - located on the side away from the axis.

Wing - any flat surfaced structure emerging from the side or summit of an organ; seeds, stems.

Plant habit

Acaulescent - the leaves and inflorescence rise from the ground, appearing to have no stem.

Acid plant - plants with acid saps, normally due to the production of ammonium salts (malic and oxalic acid)

Acme - the period when the plant or population is at its maximum vigor.

Actinomorphic - parts of plants that are radially symmetrical in arrangement.

Arborescent - growing into a tree-like habit, normally with a single woody stem.

Ascending - growing uprightly, in an upward direction, heading in the direction of the top.

Vegetative morphology

Roots generally do not offer many characters used in plant identification and classification but are important in determining plant duration though in some groups they very important for proper identification including the grasses.

Adventitious - roots that form from other than the hypocotyl or from another roots. Roots forming on the stem are adventitious.

Aerial - roots growing in the air.

Crown - the place where the roots and stem meet, which may or may not be clearly visible.

Fibrous - roots are thread-like and normally tough.

Fleshy - roots are relatively thick and soft, normally made up of storage tissue. Roots are typical long and thick but not thickly rounded in shape.

Haustorial - specialized roots that invade other plants and absorb nutrients from those plants.

Lignotuber - root tissue that allows plants to regenerate after fire or other damage.

Primary - roots that develops from the radically of the embryo, normally the first root to emerge from the seed as it germinates.

Root Hairs - very small, often one cell wide, roots that do most of the water and nutrient absorption.

Secondary - roots forming off of the primary root, often called branch roots.

Tap - a primary root that more or less enlarges and grows downward into the soil.

Tuberous - roots that are thick and soft, with storage tissue. Typically thick round in shape.

Bulb - an underground stem normally with a short basal surface and with thick fleshy leaves.

Bundle scar -

Caudex - the hard base produced by herbaceous perennials used to overwinter the plant.

Caulescent - with a distinctive stem.

Cladode -

Cladophyll - a flattened stem that is leaf-like and green- used for photosynthesis, normally plants have no or greatly reduced leaves.

Climbing - typically long stems, that cling to other objects.

Corm - a compact, upright orientated stem that is bulb-like with hard or fleshy texture and normally covered with papery, thin dry leaves. Most often produced under the soil surface.

Cuticle - a waxy membrane covering some leaves and roots that is water-tight.

Decumbent - stems that lay on the ground but have the ends turning upward.

Dormant - a state of no growth or reduced growth

Early wood -

Epidermis - a layer of cells that cover all primary tissue separating them from the outside environment.

Erect - growing upright.

Flower bud -

Fruticose - woody stemmed with a shrub-like habit. Branching near the soil with woody based stems.

Guard cell -

Herbaceous - non-woody and dying to the ground at the end of the growing season. Annual plants die, while perennials regrow from from parts on the soil surface or below ground the next growing season.

Heartwood -

Latent buds -

Lenticel -

Internode - spaces between the nodes.

Late wood -

Lateral bud -

Leaf axils - the space created between a leaf and its branch. This is especially pronounced on monocots like bromeliads.

Leaf bud -

Leaf scar - the mark left on a branch from the previous location of a bud or leaf.

Lenticels - lens-shaped or warty patches of parenchymatous tissue on the surface of the stem.

Node - were leaves and buds are attached to the stem.

Pith - the spongy tissue at the center of a stem.

Chambered pith -

Continuous pith -

Diaphragmed pith -

Spine - an adapted leaf that is usually hard and sharp and is used for protection, and occasionally shading of the plant

Prickle - an extension of the cortex and epidermis that ends with a sharp point.

Prostrate - growing flat on the soil surface.

Rhizome - A horizontally orientated, prostrate stem with reduced scale-like leaves, normally growing under ground but also at the soil surface. Also produced by some species that grow in trees or water.

Rootstock - the underground part of a plant normally referring to a caudex or rhizome.

Runner - an above ground stem usually rooting and producing new plants at the nodes.

Scandent - a stem that climbs.

Stolon - a horizontally growing stem similar to a rhizome, but growing above or along the ground.

Tendril - a thigmotropic organ which attached a climbing plant to a support

Anther - The distal end of the stamen where pollen is produced, normally composed of two parts called anther-sacs and pollen-sacs (thecae).

Bract - The leaf-like or scale-like leafy appendages that are located just below a flower, a flower stalk, or an inflorescence; they usually are reduced in size and sometimes showy or brightly colored.

Calyx -The whorl of sepals at the base of a flower.

Carpel -The ovule-producing reproductive organ of a flower, consisting of the stigma, style and ovary.

Corolla -The whorl of petals of a flower.

Disk - an enlargement or outgrowth from the receptacle of the flower, located at the center of the flower of various plants. The term is also use as the central area of the head in composites were the tubular flowers are attached.

Filament - The stalk of a stamen

Floral axis -

Floral envelope -

Flower -

Fruit - a structure contain all the seeds produced by a single flower.

Gynoecium - The whorl of carpels. May comprise one (syncarpous) or more (apocarpous) pistils. Each pistil consists of an ovary, style and stigma (female reproductive organs of the flower).

Apocarpus - The gynoecium comprises more than one pistil.

Cell -

Compound pistil -

Funicle - the stalk that connects the ovule to the placenta.

Funiculus -

Loculus - the cavities located with in a carpel, ovary or anther.

Locule -

multicarpellate -

Placentra -

Placentation -

Axile -

Basal -

Free-central -

Pariental -

Septum -

Simple pistil -

Syncarpous - The gynoecium comprises one pistil.

Unicarpellate -

Hypanthium -

Nectar - a fluid produce by nectaries high in sugar content, used to attract pollinators.

Nectary - a gland that secrets nectar, most often found in flowers but also produced on other parts of plants too.

Nectar disk - when the floral disk contains nectar secreting glands, often modified as its main function in some flowers.

Ovary -

Ovules -

Pedicel - the stem or stalk that holds a single flower in an inflorescence.

Peduncle - The part of a stem that bears the entire inflorescence, normally having no leaves or the leaves are reduce to bracts. When the flower is solitary, it is the stem or stalk holding the flower.

Peduncular - referring to or having a peduncle.

Pedunculate - having a peduncle.

Perianth -

Achlamydeous - without a perianth.

Petal -

Pistil -

Pollen -

Rachis -

Receptacle - the end of the pedicel that joins to the flower were the different parts of the flower are joined together, also called the torus. In Asteraceae the top of the pedicel upon which the flowers are joined.

Capitulum - the flowers are arranged into a head composed of many separate unstalked flowers, the single flowers are called florets and are packed close together. The typical arrangement of flowers in the Asteraceae.

Compound Umbel - is an umbel where each stalk of the main umbel produces another smaller umbel of flowers.

Corymb - a grouping of flowers where all the flowers are at the same level, the flower stalks of different lengths forming a flat-topped flower cluster.

Cyme - is a cluster of flowers were the end of each growing point produces a flower. New growth comes from side shoots and the oldest and first flowers to bloom are at the top.

Single - one flower per stem or the flowers are greatly spread-apart as to appear they do not arise from the same branch.

Spike - when flowers arising from the main stem are without individual flower stalks. The flowers attach directly to the stem.

Solitary - same as single, with one flower per stem.

Raceme - is a flower spike with flowers that have stalks of equal length. The stem tip continues to grow and produce more flowers with the bottom flowers open first and blooming progresses up the stem.

Panicle - is a raceme with branches and each branch having a smaller raceme of flowers. The terminal bud of each branch continues to grow, producing more side shoots and flowers.

Umbel - were the flower head has all the flower stalks rising from the same point of the same length, the flower head is rounded like an umbrella or almost circular.

Verticillaster - a whorled collection of flowers around the stem, the flowers produced in rings at intervals up the stem. As the stem tip continues to grow more whorls of flowers are produced. Typical in Lamiaceae.

Autogamy – self-pollination, when the flowers of the same plant pollinate flowers on the same plant or themselves.

Cantharophilous – beetle pollinated

Chiropterophilous - bat pollinated.

Cleistogamous – self-pollination of a flower that does not open.

Dichogamy – Flowers that cannot pollinate themselves because pollen is produced at a time when the stigmas are not receptive of pollen.

Entomophilous – insect pollinated.

Hydrophilous – Water pollinated, pollen is moved in water from one flower to the next.

Malacophilous – pollinated by snails and slugs.

Ornithophilous – pollinated by birds.

Pollination – the movement of pollen from the anther to the stigma.

Protandrous – when pollen is produced and shed before the carpels are mature.

Progynous – when the carpels mature before the stamens produce pollen.

Embryo development

Antipodal cell -

Chalazal -

Coleoptile -

Coleorhiza -protecting layer of a seed

Cotyledon -

Double ferilization -

Embryo –

Embryo sac -

Endosperm –

Filiform apparatus -

Germination –

Plumule -the part of an embryo that give rise to the shoot system of a plant

Polar nuclei -

Radicle -

Scutellum -

Synergid -

Tegmen -

Testa -

Triploid -

Xenia -

Zygote –

Fruits and seeds

Fruits are the matured ovary of seed bearing plants and they include the contents of the ovary, which can be floral parts like the receptacle, involucre, calyx and others that are fused to it. Fruits are often used to identify plant taxa and help to place the species in the correct family or differentiate different groups with in the same family.

Terms for fruits

Accessory structures - parts of fruits that do not form from the ovary.

Beak - normally the slender elongated end of a fruit, typically a persistent style-base.

Circumscissile - a type of fruit dehiscences were the top of the fruit falls away like a lid or covering.

Dehiscent - the way a fruit openings and releases its contents, normally in a regular and distinctive fashion.

Endocarp - includes the wall of the seed chamber, the inner part of the pericarp.

Exocarp - the pericarp's outer part.

Fleshy - soft and juicy.

Indehiscent - fruits that do not have specialized structures for opening and releasing the seeds, they remain closed after the seeds ripen and are opened by animals, weathering, fire or other external means.

Mesocarp - the middle layer of the pericarp.

Pericarp - the body of the fruit from its outside surface to the chamber were the seeds are, including the outside skin of the fruit and the inside lining of the seed chamber.

Suture - the seam along which the fruit opens, normally in most fruits it is were the carpel or carpels are fused together.

Valve - one of the segments of the capsule.

Fruit types

Fruits are divided into different types depending on how they form, were or how they open and what parts they are composed of.

Achaenocarp - see achene.

Achene - dry indehiscent fruit, they have one seed and form from a single carpel, the seed is distinct from the fruit wall.